| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. D Cramling vs Petursson |
| 1-0 | 32 | 1976 | World Championship (U17) | A34 English, Symmetrical |
| 27. L Arnold vs Petursson |
| 0-1 | 73 | 1976 | World Championship (U17) | B84 Sicilian, Scheveningen |
| 28. Petursson vs Hodgson |
| 1-0 | 48 | 1976 | World Championship (U17) | A15 English |
| 29. Petursson vs I Morovic Fernandez |
| 1-0 | 66 | 1976 | World Championship (U17) | E17 Queen's Indian |
| 30. Van der Wiel vs Petursson |
| 0-1 | 43 | 1976 | World Championship (U17) | B93 Sicilian, Najdorf, 6.f4 |
| 31. Petursson vs J J Waters |
| 1-0 | 77 | 1976 | World Championship (U17) | D94 Grunfeld |
| 32. I Rogers vs Petursson |
| ½-½ | 39 | 1976 | World Championship (U17) | A02 Bird's Opening |
| 33. Petursson vs F Olafsson |
| ½-½ | 23 | 1976 | Reykjavik | E92 King's Indian |
| 34. Najdorf vs Petursson |
| 1-0 | 27 | 1976 | Reykjavik | E14 Queen's Indian |
| 35. Petursson vs Tukmakov |
| 0-1 | 24 | 1976 | Reykjavik | D94 Grunfeld |
| 36. H Olafsson vs Petursson |
| ½-½ | 34 | 1976 | Reykjavik | A17 English |
| 37. Petursson vs G Gunnarsson |
| 1-0 | 113 | 1976 | Reykjavik | A10 English |
| 38. I Johannsson vs Petursson |
| 1-0 | 49 | 1976 | Reykjavik | E67 King's Indian, Fianchetto |
| 39. Petursson vs Antoshin |
| 1-0 | 53 | 1976 | Reykjavik | A10 English |
| 40. Westerinen vs Petursson |
| 1-0 | 33 | 1976 | Reykjavik | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 41. Petursson vs M Vukcevich |
| 0-1 | 25 | 1976 | Reykjavik | A21 English |
| 42. Petursson vs H Angantysson |
| ½-½ | 44 | 1976 | Reykjavik | A10 English |
| 43. Petursson vs Keene |
| 0-1 | 26 | 1976 | Reykjavik | A10 English |
| 44. S Matera vs Petursson |
| ½-½ | 19 | 1976 | Reykjavik | A07 King's Indian Attack |
| 45. B Thorsteinsson vs Petursson |
| 0-1 | 63 | 1976 | Reykjavik | B85 Sicilian, Scheveningen, Classical |
| 46. Petursson vs Timman |
| 0-1 | 52 | 1976 | Reykjavik | A10 English |
| 47. G Sigurjonsson vs Petursson |
| 1-0 | 31 | 1976 | Reykjavik | B93 Sicilian, Najdorf, 6.f4 |
| 48. Petursson vs C Micheli |
| ½-½ | 42 | 1976 | Haifa Olympiad | E92 King's Indian |
| 49. Petursson vs J Schammo |
| 1-0 | 34 | 1976 | Haifa Olympiad | A21 English |
| 50. T Shaw vs Petursson |
| 1-0 | 69 | 1976 | Haifa Olympiad | A07 King's Indian Attack |
Kibitzing
